Experts say the policy on testing motorbike emissions must be carried out slowly and carefully with regular monitoring of residents' responses.
The Transport Ministry plans to enforce Euro II standards that allow a motorbike to emit a maximum of 0.05 percent sulfur concentration. Sulfur is blamed for causing acid rain and lung problems.
The Euro II standard was applied to new cars and motorbikes early last year after a two-year trial at five major cities in the country Hanoi, Hai Phong, Da Nang, Ho Chi Minh and Can Tho.
Lecturer Nguyen Dinh Hoe from the environment department of Hanoi University of Natural Sciences said officials should consider the plan carefully before implementing it.
"From a scientific perspective, the testing is right.
"But most Vietnamese people travel by motorbikes and many depend on the bikes to make a living.
"And the oldest motorbikes that produce the worst emissions are driven by poor people."
Hoe suggests the officials publicize the plan and conduct an opinion poll before launching a trial.
"Don't let the plan lose intensity after a few days like the one that banned people with small chests from driving motorbikes."
The government last October banned people having chests smaller than 72 centimeters from driving motorbikes. The ban was lifted in November after many objections from the public.
Nguyen Ngoc Sinh, chairman of Vietnam Association for Conservation of Nature and Environment, says "Testing motorbike emissions to control air pollution is a need and many countries have been doing that regularly."
Residents are both the victims and the cause of air pollution, Sinh says.
"The success of the policy depends on the awareness of the residents and the way the officials carry it out.
Trinh Ngoc Giao, head of the ministry's Registration Bureau, says an opinion poll on the Internet showed 57.55 percent of more than 10,500 people surveyed were in the favor of having the test conducted once a year.
Motorbikes are the main air polluter in Vietnam, he says. Besides sulfur, benzene and aromatics in the fuel also cause health problems while metal and carbon dioxide contribute to the greenhouse effect.
By applying Euro II, Vietnam can totally control motorbike emission by 2015 when the emission in large cities will be cut by 40 percent compared to 2007, Giao says.
Under the new plan, motorbikes that fail to meet the standard cannot run on the streets until they are repaired and tested again.